The Evolution in Electrochemical Performance of Honeycomb-Like Ni(OH)2 Derived from MOF Template with Morphology as a High-Performance Electrode Material for Supercapacitors

Pouch-Type Asymmetric Supercapacitor Based on Nickel-Cobalt Metal-Organic Framework

Bimetal-organic frameworks (BMOFs) have attracted considerable attention as electrode materials for energy storage devices because of the precise control of their porous structure, surface area, and pore volume. BMOFs can promote multiple redox reactions because of the enhanced charge transfer between different metal ions. Therefore, the electroactivity of the electrodes can be significantly improved. Herein, we report a NiCo-MOF (NCMF) with a three-dimensional hierarchical nanorod-like structure prepared using a facile solvo-hydrothermal method. The as-prepared NCMF was used as the positive electrode in a hybrid pouch-type asymmetric supercapacitor device (HPASD) with a gel electrolyte (KOH+PVA) and activated carbon as the negative electrode. Because of the matchable potential windows and specific capacitances of the two electrodes, the assembled HPASD exhibits a specific capacitance of 161 F·g^-1 at 0.5 A·g^-1, an energy density of 50.3 Wh·kg^-1 at a power density of 375 W·kg^-1, and a cycling stability of 87.6% after 6000 cycles. The reported unique synthesis strategy is promising for producing high-energy-density electrode materials for supercapacitors.

Synthesis of Ni3S2 and MOF-Derived Ni(OH)2 Composite Electrode Materials on Ni Foam for High-Performance Supercapacitors

Honeycomb-like Ni(OH)₂/Ni₃S₂/Ni foam (NF) was fabricated via a two-step hydrothermal process and subsequent alkalization. Ni₃S₂ with a honeycombed structure was in-situ synthesized on the NF surface by a hydrothermal process. MOF-derived Ni(OH)₂ nanosheets were then successfully grown on the Ni₃S₂/NF surface by a second hydrothermal process and alkaline treatment, and a large number of nanosheets were interconnected to form a typical honeycomb-like structure with a large specific surface area and porosity. As a binder-free electrode, the prepared honeycomb-like Ni(OH)₂/Ni₃S₂/NF exhibited a high specific capacitance (2207 F·g^-1 at 1 A·g^-1, 1929.7 F·g^-1 at 5 mV·s^-1) and a remarkable rate capability and cycling stability, with 62.3% of the initial value (1 A·g^-1) retained at 10 A·g^-1 and 90.4% of the initial value (first circle at 50 mV·s^-1) retained after 5000 cycles. A hybrid supercapacitor (HSC) was assembled with Ni(OH)₂/Ni₃S₂/NF as the positive electrode and activated carbon (AC) as the negative electrode and exhibited an outstanding energy density of 24.5 Wh·kg^-1 at the power density of 375 W·kg^-1. These encouraging results render the electrode a potential candidate for energy storage.

Metal-Organic Framework Materials for Electrochemical Supercapacitors

Exploring new materials with high stability and capacity is full of challenges in sustainable energy conversion and storage systems. Metal-organic frameworks (MOFs), as a new type of porous material, show the advantages of large specific surface area, high porosity, low density, and adjustable pore size, exhibiting a broad application prospect in the field of electrocatalytic reactions, batteries, particularly in the field of supercapacitors. This comprehensive review outlines the recent progress in synthetic methods and electrochemical performances of MOF materials, as well as their applications in supercapacitors. Additionally, the superiorities of MOFs-related materials are highlighted, while major challenges or opportunities for future research on them for electrochemical supercapacitors have been discussed and displayed, along with extensive experimental experiences.

Metal-Organic Framework Reinforced Acrylic Polymer Marine Coatings

Metal-organic frameworks (MOFs), a class of crystalline, porous, 3D materials synthesized by the linking of metal nodes and organic linkers are rapidly emerging as attractive materials in gas storage, electrodes in batteries, super-capacitors, sensors, water treatment, and medicine etc. However the utility of MOFs in coatings, especially in marine coatings, has not been thoroughly investigated. In this manuscript we report the first study on silver MOF (Ag-MOF) functionalized acrylic polymers for marine coatings. A simple and rapid microwave technique was used to synthesize a two-dimensional platelet structured Ag-MOF. Field tests on the MOF reinforced marine coatings exhibited an antifouling performance, which can be attributed to the inhibition of marine organisms to settle as evidenced by the anti-bacterial activity of Ag-MOFs. Our results indicate that MOF based coatings are highly promising candidates for marine coatings.